Ecosystem recovery at hypersaline salt marsh remediation projects impacted by the Gulf War Oil Spill

ABSTRACT #1141405 The 1990 Gulf War Oil Spill was the largest marine oil spill in history, spilling an estimated 6–11 million barrels of crude oil into the Arabian Gulf and impacting approximately 800 km of shoreline in Saudi Arabia between the border with Kuwait and Abu Ali Island near Jubail. Many intertidal areas were heavily oiled, severely damaging salt marsh ecosystems and facilitating the growth of thick algal mats, which, in turn, created a physical barrier that restricted tidal exchange and prevented recolonization of marsh flora and fauna at these sites. Remediation projects have been ongoing since early 2010 at 19 project areas throughout the area of impact. Remediation activities are focused on refreshing existing or creating new tidal channels to restore hydrology and tilling the substrate to expose moderately oiled sediment and enhance the degradation of oil and break up laminate algal mats. Additional activities include removal of heavily oiled sediments, re-use of excavated unoiled and lightly oiled sediments to create additional topography in restored marshes, and vegetation planting in selected areas. Monitoring plots for long-term study were established at remediation sites, impacted but untreated sites (set-asides), and nearby reference (comparison) sites. Initial monitoring data were collected before and after remediation activities, which were primarily undertaken between 2010 and 2013. Biannual (spring and fall) monitoring was resumed in fall 2018 and will continue through spring 2022 to characterize ecosystem recovery at these sites. Based on results from fall 2018 and spring 2019, most remediation sites show some level of recovery, indicated by the return of annual vegetation and resident marsh invertebrates in lower elevation plots, and thinner algal mat types and insect burrowing activity at the upper elevations. While the lower portions of untreated sites are beginning to show recruitment of annual vegetation and invertebrates (e.g. crabs), thick, laminated algal mat cover occurs in the middle-upper elevations at untreated sites. Multimetric indices (MMIs) summarizing ecosystem health and stressors were developed to summarize recovery of these projects and evaluate progress at remediation sites relative to set-aside and comparison sites. MMI results indicate that remediation work was effective at reducing stressors in remediation sites compared to set-asides; however, the level of ecosystem recovery is variable across sites, in part depending on the time since restoration.

Qualitative growth potential test for brackish Vaucheria species

The yellow-green algae _Vaucheria_ can be found on tidal flats as densely interwoven mats. Such dense mats can stabilise sediments and result in a ridge-and-runnel bedform. While _Vaucheria_ is visually covering the ridges as thick algal mats, the runnels are apparently deprived of the filamentous algae. In the present protocol I describe the procedure for sampling and testing sediments for the presence of _Vaucheria_ propagules. The method provides a qualitative test for the presence of algae propagules of _Vaucheria_ in bare sediments but is non-exclusive as also other algae \(e.g., microphytobenthos) will grow when present. To check for cross-contamination and sufficient growth conditions, appropriate negative and positive controls are implemented.

The “green tides” influence on the heavy metal pollution of the coastal zone

We confirmed the hypothesis that algal mats provoke additional accumulation of heavy metals in the bottom sediments and release of labile metals. This process, in turn, enforce a pollution of the coastal zone. Our results give a new direction to the studies of the green tides worldwide problem.

Bacteria defend carrion from scavengers

Carrion in the form of dead seal pups and algal mats placed on soft bottom habitats at Explorers Cove and Salmon Bay, McMurdo Sound, attract scavenging invertebrates that are driven away by hydrogen sulphide produced by sulphate-reducing bacteria sequestered below a layer of Beggiatoa/Thioploca-like filamentous bacteria. This system is usually found for lipid-rich marine mammal carrion, but also occurred with natural algal mats.

Rotifers (Rotifera) from the inland waters and terrestrial habitats of East Antarctic oases (Enderby Land and Prydz Bay)

The paper presents the results of rotiferological studies carried out during the set of the Belarusian Antarctic Expeditions (2007–2017) in East Antarctica (Enderby Land and Prydz Bay). The plankton samples were collected from 52 water bodies (lakes and meltwater ponds), and from terrestrial habitats (lichen fouling, algal mats) from several sites. A total of 20 species were found, 12 of them belonging to Monogononta, 8 – to Bdelloidea. Despite the presence of some cosmopolitan species and Antarctic endemics, the set of species and forms seems to be the firstly noted taxa in East Antarctica.